Transition On The Fly

ABSTRACT

A system is provided for varying the width of a molded concrete slab on the fly as the slab is being molded. Position and height of the paving machine relative to an external reference system are determined and controlled using at least two 3D stringless reference objects. An additional sensor provides a signal corresponding to a frame width and thus a concrete slab width, and an actuator controls the frame width actively as the paving machine advances.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to control systems for slipformpaving machines and more particularly, but not by way of limitation, toa system for controlling the position of the slipform paving machinewhile simultaneously controlling changes in paving width as the machinemoves forward during a paving operation.

2. Description of the Prior Art

In construction machines for forming structures on a ground surface,such as a concrete slipform paving machine, important factors includethe control of the height of the working implements and thus the gradeor height of the concrete structure being molded, and the control of thesteering direction of the machine.

Such slipform paving machines typically take a reference reading from astringline which has been placed on one or both sides of the intendedpath of the machine. In the past, when it has been desired to create amolded concrete structure having a transition from one structure widthto a second structure width, two stringlines have been laid out oneither side of the desired path of the machine, and the change in widthof the concrete structure is created by varying the width between thetwo stringlines.

Another previously used technique is to have a single stringline on oneside of the slipform paving machine, and to manually telescope themachine to control changes in width on the second side of the machine.In this case the height on the second side might be controlled by aslope sensor.

There is a continuing need for improved systems to allow for transitionin paving width during a slipform paving operation.

SUMMARY OF THE INVENTION

A slipform paving machine apparatus is disclosed including a machineframe having first and second side frame members. The machine frame isvariable in frame width. At least one ground engaging unit, such as atrack or wheel, is provided on each side of the machine. At least one ofthe ground engaging units is steerable. Front and rear first side heightadjustable supports support the first side frame member from at leastone first side ground engaging unit. At least one second side heightadjustable support supports the second side frame member from at leastone second side ground engaging unit. A mold is supported from themachine frame beneath the machine frame and laterally between the atleast one first side ground engaging unit and the at least one secondside ground engaging unit. The mold is configured to mold concrete intoa concrete structure having an upper surface and lateral concrete sidesas the machine moves forward in an operating direction. The mold isvariable in width so as to vary a paving width of the concretestructure. At least two three-dimensional (3D) stringless referenceobjects are configured to correspond to positions of at least two pointson the machine frame relative to an external reference system. A widthactuator is configured to vary the paving width. A width sensor isconfigured to generate a width signal corresponding to a change in thepaving width. A controller is configured to receive input signalscorresponding to the positions of the 3D stringless reference objects inthe external reference system, and to receive the width signal from thewidth sensor. The controller is also configured to control heightadjustment of one or more of the height adjustable supports, to controlsteering of the at least one steerable ground engaging unit, and tocontrol the width actuator so that the paving width can be varied as themachine moves forward in the operating direction.

In another aspect, a method is disclosed of operating a slipform pavingmachine. The method may include the steps of:

(a) providing a slipform paving machine including:

a main frame module and at least one laterally extendable side framemember, the at least one laterally extendable side frame member beinglaterally extendable relative to the main frame module to vary a framewidth;

at least one first side ground engaging unit and at least one secondside ground engaging unit;

front and rear first side height adjustable supports supporting themachine frame from the at least one first side ground engaging unit;

at least one second side height adjustable support supporting themachine frame from the at least one second side ground engaging unit;and

a concrete mold supported from the machine frame beneath the machineframe and laterally between the at least one first side ground engagingunit and the at least one second side ground engaging unit, the moldhaving a variable mold width;

(b) moving the slipform paving machine forward in an operating directionand molding concrete into a concrete slab structure extending betweenthe ground engaging units and behind the concrete mold, the structurehaving an upper surface and lateral concrete sides;

(c) during step (b) sensing a location in an external reference systemof at least two 3D stringless reference objects, each of the objectsbeing fixed relative to at least one of the main frame module and the atleast one laterally extendable side frame member;

(d) controlling a direction and height of the machine frame with anautomatic control system in response to signals corresponding to thelocations of the two 3D stringless reference objects; and

(e) during step (b) continuously adjusting the mold width from a firstslab width to a second slab width and forming a continuous transition inthe concrete slab structure.

In either of the above embodiments a distance between the at least two3D reference objects may either be fixed, or may be variable.

When the distance between the at least two 3D reference objects isvariable, the width sensor may comprise a controller module configuredto detect the distance between the at least two 3D stringless referenceobjects based upon the input signals corresponding to the positions ofthe at least two 3D stringless reference objects in the externalreference system. In this embodiment, and additional width sensor mayoptionally also be used.

In another aspect of the invention a slipform paving machine apparatusincludes a machine frame having a main frame module and at least onelaterally extendable side frame member. The at least one laterallyextendable side frame member is laterally extendable relative to themain frame module to vary a frame width. At least one first side groundengaging unit and at least one second side ground engaging unit areprovided. Front and rear first side height adjustable supports supportthe machine frame from the at least one first side ground engaging unit.At least one second side height adjustable support supports the machineframe from the at least one second side ground engaging unit. A variablewidth mold is supported from the machine frame beneath the machine frameand laterally between the at least one first side ground engaging unitand the at least one second side ground engaging unit. The mold isconfigured to mold concrete into a concrete structure having an uppersurface and lateral concrete sides as the machine moves forward in anoperating direction. The machine includes at least two 3D stringlessreference objects configured to correspond to positions of the objectsrelative to an external reference system. The machine further includes acarrier frame having the at least two 3D stringless reference objectsfixedly attached to the carrier frame so that a distance between the atleast two 3D stringless reference objects is fixed. The carrier frame issupported from at least one of the main frame module and the at leastone laterally movable side frame member.

In any of the above embodiments the mold may be attached to the machineframe such that the mold width varies as the frame width is varied.

The mold may also be supported from the machine frame in such a mannerthat to some degree the mold width can be varied independent of theframe width.

In any of the above embodiments both of the side frame members may belaterally movable relative to the main frame module to vary the framewidth.

In any of the above embodiments the width sensor may comprise anadditional 3D stringless reference object mounted on the machine framesuch that the additional 3D stringless reference object moves relativeto the at least two 3D stringless reference objects when the frame widthis varied.

In any of the above embodiments the width sensor may comprise anextension sensor associated with the width actuator or with the machineframe or with the mold for detecting an extension of the width actuator.

In any of the above embodiments the width sensor may comprise astringline sensor mounted on the machine frame such that the stringlinesensor moves relative to the at least two 3D stringless referenceobjects when the frame width is varied, so that a stringline fixed inthe external reference system can be used to control changes in framewidth.

The at least two 3D stringless reference objects may be spaced apartlongitudinally with a spacing component parallel to the operatingdirection.

The at least two 3D stringless reference objects may be longitudinallyfixed relative to one of the side frames.

The at least two 3D stringless reference objects may be longitudinallyfixed relative to the main frame module.

The at least two 3D stringless reference objects may be spaced apartlaterally with a spacing component perpendicular to the operatingdirection.

The at least two 3D stringless reference objects may be laterally fixedrelative to the main frame module.

The at least two 3D stringless reference objects may be laterally fixedrelative to one of the laterally movable side frame members.

The machine may further include a carrier frame having the at least two3D stringless reference objects fixedly attached to the carrier frame sothat a distance between the at least two 3D stringless reference objectsis fixed. The carrier frame may be fixed relative to either the mainframe module or one of the laterally movable side frame members.

In any of the above embodiments including the carrier frame, the carrierframe may be fixed to one of the laterally movable side frame members,and the machine may further include a traveling support between thecarrier frame and the main frame module for supporting the carrier framefrom the main frame module while allowing relative lateral movementbetween the carrier frame and the main frame module.

In any of the above embodiments the at least two 3D stringless referenceobjects may include global navigation satellite system (GNSS) sensors.

In any of the above embodiments the at least two 3D stringless referenceobjects may include reflectors for a ground based optical surveyingsystem.

In any of the above embodiments one of the at least two 3D stringlessreference objects may include a global navigation satellite system(GNSS) sensor and the other of the at least two 3D stringless referenceobjects may include a reflector for a ground based optical surveyingsystem.

In any of the above embodiments the slipform paving machine may includea cross slope sensor mounted on the machine frame, and the controllermay be configured to generate a cross slope adjustment signal to controla cross slope of the machine frame by adjustment of one or more of theheight adjustable supports.

In any of the above embodiments the width actuator may include a pistonand cylinder configured to extend and contract the frame width.

In any of the above embodiments the width actuator may include asteering system configured to steer the ground engaging units relativeto each other so as to vary the frame width.

Numerous objects, features and advantages of the present invention willbe readily apparent to those skilled in the art upon a reading of thefollowing disclosure when taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of a first embodiment of a slipformpaving machine having a main frame module and having left and right sideframe members both laterally extendable relative to the main framemodule. The side frame members are also longitudinally extendable toextend the length of the slipform paving machine.

FIG. 2 is a left side elevation view of the slipform paving machine ofFIG. 1.

FIG. 3 is a rear elevation view of the slipform paving machine of FIGS.1 and 2.

FIG. 3A is a view similar to FIG. 3 showing an alternative location ofthe 3D stringless reference objects carried by a carrier frame mountedon the main frame module.

FIG. 3B is a view similar to FIG. 3 showing another alternativearrangement of the 3D reference objects mounted on a carrier frame fixedto the left side frame member and having a traveling support providedfrom the main frame module.

FIG. 3C is a view similar to FIG. 3B showing another alternativearrangement of the 3D reference objects mounted on the carrier frame,with the carrier frame being laterally adjustably positioned on the mainframe module.

FIG. 3D is a schematic view corresponding to the embodiment of FIG. 3Cand illustrating the central positioning of the carrier frame to span amain trajectory of the machine when the expandable frame is laterallyexpanded in an asymmetric manner.

FIG. 4 is a schematic plan view of the details of the steering systemand swing leg control system hardware associated with the left frontswing leg and crawler track of the machine of FIG. 1.

FIG. 5 is a schematic plan view similar to FIG. 1 showing an alternativeembodiment of the slipform paving machine which is extendable in widthto only the left side of the main frame module.

FIGS. 6A-6F comprise a set of schematic plan views illustratingalternative locations of the 3D stringless reference objects on a dualtelescoping slipform paver apparatus like that of FIGS. 1-3.

FIGS. 7A-7F comprise a set of schematic plan views illustratingalternative locations of the 3D stringless reference objects on a singletelescoping slipform paver apparatus like that of FIG. 5.

FIG. 8A is a schematic plan view showing a molded concrete structureincreasing in width symmetrically on both sides of a main paving path.

FIG. 8B is a view similar to FIG. 8A showing a change in width to oneside of a main paving path.

FIG. 8C is a view similar to FIG. 8A showing a non-symmetrical expansionin width to both sides of a main paving path.

FIG. 9 is a schematic illustration of a control system associated withthe slipform paving machine of either FIG. 1 or 5.

FIG. 10 is a schematic plan view similar to FIG. 6A illustratingalternative locations of the 3D stringless reference objects having avariable spacing between the objects on a dual telescoping slipformpaver apparatus like that of FIGS. 1-3.

FIG. 11 is a schematic plan view similar to FIG. 7A illustratingalternative locations of the 3D stringless reference objects having avariable spacing between the objects on a single telescoping slipformpaver apparatus like that of FIG. 5.

FIG. 12 is a schematic plan view of a three-track single telescopingslipform paver apparatus.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a slipform paving machine apparatus 10including a machine frame 12. The machine frame 12 includes first andsecond side frame members 14 and 16 which are laterally extendablerelative to a main frame module 18. The first and second side framemembers 14 and 16 may also be referred to as left and right side framemembers 14 and 16.

The first side frame member 14 is attached to forward and rear maletelescoping members 20 and 22 which are received within the main framemodule 18 in a telescoping manner. Forward and rear left side actuatingrams 24 and 26 are connected between the main frame module 18 and theleft side frame member 14 to control lateral extension and retraction ofthe left side frame member 14 relative to the main frame module 18.

Forward and rearward male telescoping members 21 and 23 are similarlyattached to the right side frame member 16 and are telescopinglyreceived in the main frame module 18. Forward and rear right sideactuating rams 28 and 30 are connected between the main frame module 18and the right side frame member 16 to control lateral extension andretraction of the right side frame member 16 relative to the main framemodule 18.

The rams 24, 26, 28 and 30 may all be referred to as width actuatorsconfigured to vary a distance between the side frame members 14 and 16and to thereby vary a frame width 32. Each of the rams such as 24includes a piston 24′ and a cylinder 24″ configured to expand andcontract the frame width 32. It will be understood that the widthactuators do not have to be hydraulic rams. Electric linear actuators,rotary actuators, and any other suitable actuators may be used.

The side frame members 14 and 16 are also constructed so as to beadjustable in length parallel to a paving direction or operatingdirection indicated by the arrow 34. Thus the first or left side framemember 14 includes a rearwardly extendable first side frame portion 36and the second or right side frame member 16 includes a rearwardlyextendable right side frame portion 38.

The paving machine 10 includes four ground engaging units 40A, 40B, 40Cand 40D which in the illustrated embodiment are crawler tracks. Wheelscould also be used as ground engaging units. The machine frame 12further includes four frame swing arms 42A, 42B, 42C and 42D which arepivotally attached to the machine frame 12 and which carry the groundengaging units 40A-40D at their outer ends.

Associated with each of the ground engaging units 40A-40D are heightadjustable supports or lifting columns 44A, 44B, 44C and 44D. In theembodiment of FIG. 1, front and rear first side height adjustablesupports 44A and 44C, respectively, support the first side frame member14 from the ground engaging units 40A and 40C, respectively. Front andrear second side height adjustable supports 44B and 44D support thesecond side frame member 16 from the ground engaging units 40B and 40D,respectively.

Further features of the slipform paving machine 10 are seen in FIGS. 2and 3. As seen in FIG. 2, a number of tools are carried by the machineframe 12, including a plow or concrete spreader 46, a front wall 48, asystem of vibrators or concrete liquefying devices 50, first and secondmold portions 52 and 54, an oscillating beam 56 and a super smoother 57.Other components such as a dowel bar inserter (not shown) may also besupported from the slipform paving machine.

Also carried on the machine frame 12 is a tractor operations module 58which may include a diesel engine for powering the various hydraulic andelectrical systems, a control platform, an operator station and thelike.

As is seen in FIG. 2, a mass of concrete 60 is placed in front of theslipform paving machine 10 and then the various components justdescribed, and particularly the mold 52, 54, forms the concrete 60 intoa molded concrete structure 62 having an upper surface 64 and havingformed sides such as 66.

The mold 52, 54 may be described as a variable width mold supported fromthe machine frame 12 beneath the machine frame 12 and laterally betweenthe ground engaging units 40A and 40C on the left side and the groundengaging units 40B and 40D on the right side. The mold 52, 54 isconfigured to mold the concrete 60 into the concrete structure 62 havingan upper surface 64 and lateral concrete sides such as 66 as the machine10 moves forward in the operating direction 34. The forward and rearwardmold portions 52 and 54 are attached to the machine frame 12 adjacenttheir laterally outer end portions by attachments such as 68 and 70. Theinner ends 72 and 74 of mold portions 52 and 54 are slidably supportedfrom a central vertical support 76 relative to frame 12. The centralsupport 76 may be vertically adjusted to create a crown in the moldedstructure 62. The laterally inner end portions 72 and 74 overlap so thatthey may slide relative to each other as the frame width 32 of machineframe 12 is varied. Thus in the embodiment shown in FIGS. 1-3,variations in the frame width 32 result in variations in a mold width78.

It will also be understood that the mold can be supported independentlyfrom the machine frame in such a manner that to a limited extent themold width can be adjusted independently from the frame width. In eithersituation, a change in mold width will correspond to a change in pavingwidth of the concrete structure being formed.

As is best seen in FIG. 4, which is a schematic plan view of the crawlertrack and swing leg supporting the left front corner of the machineframe 12, each of the swing legs such as 42A is pivotally connected tothe machine frame 12 at a pivot axis such as 80A. The crawler track orground engaging unit 40A is steerably connected to the free end of theswing leg 42A and may be steered about a vertical axis 82A of the heightadjustable lifting column 44A. A holding device 84A such as a hydraulicram or turn buckle maintains the pivotal orientation of the swing leg42A relative to the machine frame 12.

In the drawings, the swing legs 42 and holding devices 84 areschematically illustrated as being directly connected to the machineframe 12. It will be understood, however, that the swing legs andholding devices do not have to be directly connected to the machineframe 12. Instead, the swing legs and holding devices may be indirectlyconnected to the machine frame 12 by suitable mounting brackets. Whenone of these components is described herein as being connected to themachine frame 12, that includes both direct and indirect connections.

Steering of the crawler track 40A relative to the frame 12 about thevertical axis 82A is accomplished by extension and retraction of ahydraulic steering cylinder 86A pivotally connected at 88A to anintermediate location on the swing leg 42A and pivotally connected at90A to a steering arm 92A connected to rotate with the ground engagingunit or crawler track 40A. Alternatively, instead of the use of ahydraulic ram steering cylinder 86A, the track 40A may be steeredrelative to the frame 12 by a rotary actuator such as a worm gear orslew gear drive. Also, an electric actuator may be used instead of ahydraulic actuator to steer the crawler track. Each of the crawlertracks such as 40A may have a steering sensor such as 94A associatedtherewith, which steering sensors are configured to detect the steeringangles of their respective crawler tracks relative to their respectiveswing legs such as 42A. The steering sensors may for example each be anelectromagnetic encoder commercially available from TWK-Elektronik GmbH,Heinrichstrasse 85, 40239 Dusseldorf, Germany, as Model TMA50-SA180WSA16.

Each of the ground engaging units such as 40A may be a powered or drivenground engaging unit and may be powered such as by a hydraulic drivemotor 96A.

Instead of or in addition to use of the rams 24, 26, 28 and 30 to varythe frame width 32, the tracks 40A, 40B, 40C and 40D may be steeredrelative to each other so as to aid in the lateral extension andcontraction of the frame width. Details of construction of such asteering based frame extension and retraction arrangement are furtherset forth in U.S. patent application Ser. No. 14/299,893 entitled “FrameWidth Adjustment By Steering” filed Jun. 9, 2014, the details of whichare incorporated herein by reference.

Although the embodiment shown in FIG. 1 illustrates a four trackslipform paving machine, it will be understood that the principles setforth herein may also be utilized on two track or three track machines.For example, FIG. 12 schematically illustrates a three track singletelescoping slipform paving machine. In the machine of FIG. 12, thethree tracks 40A, 40B and 40C and related components are numberedanalogous to the similar components of FIG. 1.

Guidance System

The slipform paving machine 10 is preferably guided using athree-dimensional (3D) stringless reference system which determines theposition of the machine 10 relative to an external reference systemexternal from the machine 10. One such system is the use of a groundbased optical surveying system such as a total station 100 schematicallyillustrated in FIG. 3. Another such system is one of the globalnavigation satellite system (GNSS) systems, such as the GPS systemutilized in North America. Such GNSS systems utilize signals from aplurality of satellites schematically illustrated as 102 in FIG. 3.Utilizing either of these systems, the objects which are attached to themachine frame and used with either the total station 100 or the GNSSsatellites 102 to identify positions on the machine frame within theexternal reference system may be generally referred to as 3D stringlessreference objects. Thus, in the embodiment shown in FIGS. 1-3, theslipform paving machine 10 is shown as including two 3D stringlessreference objects S1 and S2, which in this embodiment are fixedlymounted on the left side frame member 12 and can be described as beingspaced longitudinally apart with a spacing component parallel to theoperating direction 34. As best seen in FIG. 2, the objects S1 and S2are fixed relative to points 104 and 106 on machine 12 and are supportedby masts 108 and 110.

It is noted that although the two 3D stringless reference objects S1 andS2 may be shown or described herein as being attached to the frame orsome part of the frame, it is not required that those objects bephysically attached directly to the frame members 12, 14, 16 or 18identified herein. What is important is that the reference object bemounted so that it is fixed in position relative to the frame or otheridentified component. The reference objects may be physically mounted onother components that are fixed relative to the frame. For example, ifthe two mold components 52 and 54 are fixed to move with the left andright side frame members 14 and 16, respectively, then one or both ofthe reference objects could be mounted on the mold. Thus a referenceobject S1 or S2 configured to correspond to a position of a point on themachine frame may be physically mounted on the machine frame or may bemounted on another component that is fixed relative to that point on themachine frame.

When using a ground based optical surveying system such as a totalstation 100, the 3D stringless reference objects S1 and S2 may bereflectors or prisms which reflect optical signals 101 from the totalstation 100 back to the total station 100. In that case the totalstation 100 generates signals corresponding to the location of thereference objects S1 and S2 within the external reference system, andthose signals are communicated via communication line 105 (see FIG. 9)to the controller 112 of the slipform paving machine 10 as furtherdescribed below. The communication line 105 is schematic only, and itwill be understood that such communication line may include wirelesscommunications.

When using a GNSS system involving satellites such as 102, the 3Dstringless reference objects S1 and S2 may be GNSS sensors which receivesignals 103 from a plurality of satellites such as 102 and generatesignals corresponding to the location of the reference objects S1 and S2within the external reference system. Those signals generated by theGNSS sensors S1 and S2 are then communicated to the controller of theslipform paving machine 10 as further described below.

The signals from the total station 100 and/or signals from GNSS sensorsS1 and S2 may all be referred to as input signals corresponding to thelocations of the objects S1 and S2 within the external reference system.

As used herein, the word “stringless” in the term “3D stringlessreference object” means that the reference object does not engage astringline such as the stringline 132 shown in FIGS. 1 and 3.

A controller 112 schematically illustrated in FIG. 9 receives the inputsignals corresponding to the locations of the objects S1 and S2 withinthe external reference system, and generates control signals directed tothe front and rear left side adjustable columns 44A and 44C to control aheight of the objects S1 and S2 and thus of the machine frame 12 atpoints 104 and 106 relative to the external reference system.Communication of height adjustment signals from the controller 112 tothe height adjustable columns 44 of the machine 10 are schematicallyillustrated in FIG. 9 by communication line 114. It will be understoodthat the height adjustable columns 44 each include a hydraulic ram (notshown) actuated by a hydraulic control valve which controls flow ofhydraulic fluid to and from the opposite sides of the hydraulic ram. Thehydraulic control valves may be controlled by electrical signalsconducted over communication line 114 from controller 112 in a knownmanner.

Similarly, the controller 112 may control the direction of the slipformpaving machine 10 within the external reference system by steering ofthe ground engaging units 40 via their respective steering cylinders 86.Communication of such steering signals from controller 112 to thevarious steering cylinders 86 is schematically illustrated bycommunication line 116 shown in FIG. 9. Again, electrical steeringsignals may be communicated over communication line 116, to electricallyactuate hydraulic control valves (not shown) which direct hydraulicfluid to and from the hydraulic rams 86 in a known manner to steer eachof the ground engaging units 40.

Controller 112 includes a processor 113, a computer readable memorymedium 115, a data base 117 and an input/output module or control panel119 having a display 121. An input/output device 123, such as a keyboardor other user interface, is provided so that the human operator maininput instructions to the controller. It is understood that thecontroller 112 described herein may be a single controller having all ofthe described functionality, or it may include multiple controllerswherein the described functionality is distributed among the multiplecontrollers.

The term “computer-readable memory medium” as used herein may refer toany non-transitory medium 115 alone or as one of a plurality ofnon-transitory memory media 115 within which is embodied a computerprogram product 125 that includes processor-executable software,instructions or program modules which upon execution may provide data orotherwise cause a computer system to implement subject matter orotherwise operate in a specific manner as further defined herein. It mayfurther be understood that more than one type of memory media may beused in combination to conduct processor-executable software,instructions or program modules from a first memory medium upon whichthe software, instructions or program modules initially reside to aprocessor for execution.

“Memory media” as generally used herein may further include withoutlimitation transmission media and/or storage media. “Storage media” mayrefer in an equivalent manner to volatile and non-volatile, removableand non-removable media, including at least dynamic memory, applicationspecific integrated circuits (ASIC), chip memory devices, optical ormagnetic disk memory devices, flash memory devices, or any other mediumwhich may be used to stored data in a processor-accessible manner, andmay unless otherwise stated either reside on a single computing platformor be distributed across a plurality of such platforms. “Transmissionmedia” may include any tangible media effective to permitprocessor-executable software, instructions or program modules residingon the media to be read and executed by a processor, including withoutlimitation wire, cable, fiber-optic and wireless media such as is knownin the art.

The term “processor” as used herein may refer to at leastgeneral-purpose or specific-purpose processing devices and/or logic asmay be understood by one of skill in the art, including but not limitedto single- or multithreading processors, central processors, parentprocessors, graphical processors, media processors, and the like.

The slipform paving machine 10 further includes a width sensor S3arranged to generate a width signal corresponding to a change in theframe width 32. In the embodiment illustrated in FIGS. 1-3, the widthsensor S3 comprises an additional 3D stringless reference object S3.Thus, if the 3D reference objects S1 and S2 are reflectors for anoptical based ground based external reference system such as totalstation 100, then the additional object S3 may also be a reflector orprism for such an optical based system. If, however, the objects S1 andS2 are GNSS sensors then the additional object S3 may also be a GNSSsensor. In the embodiment illustrated in FIGS. 1-3 the additional objectS3 is fixedly mounted on right side frame member 16 by a mast 118.

It is also possible to use a mixture of reference objects, some beingreflectors used with an optical system and some being GNSS sensors. Forexample, a total system 100 with reflectors S1 and S2 may be used forthe first side 14 of the machine 10 as seen in FIG. 1 because of thehigh accuracy of such a system for determining the height of the machineframe 12, and at the same time a GNSS sensor S3 may be used to determinethe location of the other side 16 of the frame. With such a system across slope sensor 122 may be used to accurately control the height ofthe other side 16 of the frame.

It will be appreciated that with position signals corresponding to thepositions of the objects S1, S2 and S3 within the external referencesystem, the controller 112 can determine the frame width 32, and thusthe additional object S3 may be generally described as a width sensor S3arranged to generate a width signal corresponding to a change in theframe width 32.

The controller 112 communicates with the hydraulic rams 24, 26, 28 and30 via communication line 120 as schematically illustrated in FIG. 9 tocontrol the rams 24, 26, 28 and 30 so as to vary and to control theframe width 32. Controller 112 sends electrical control signals viacommunication line 120 to electrically actuated hydraulic valves (notshown) associated with each of the hydraulic rams 24, 26, 28 and 30, todirect hydraulic fluid to and from the rams 24, 26, 28 and 30 to controlextension and retraction of the same in a known manner.

One or more cross slope sensors 122 may also be mounted on the machineframe, and provide an input signal to controller 112 as schematicallyillustrated in FIG. 9. In response to the cross slope signal from crossslope sensor 122, the controller 112 may vary the extension of one ormore of the height adjustable supports 44 to adjust the cross slope ofthe slipform paving machine 10 to a desired value.

Alternative Width Sensors

In another embodiment, instead of or in addition to the additionalreference object S3, a width sensor may be provided by extension sensors124, 126, 128 and 130 associated with the actuator rams 24, 26, 28 and30, respectively. In this embodiment, the height and location of theleft side frame member 14 may be determined via reference objects S1 andS2, and the frame width 32 may be controlled via the extension sensors124, 126, 128 and 130 and control of the extension of the rams 24, 26,28 and 30.

Also, the extension sensors can be physically separate from the actuatorrams. For example, separate extension sensors (not shown) can beconnected between the main frame module 18 and each of the side framemembers 14 and 16. Also there could be a single extension sensorextending between the side frame members 14 and 16.

In still another embodiment, instead of the additional 3D stringlessreference object S3, a stringline 132 may be fixed in the externalreference system relative to the ground 134. The right side frame member16 may carry a stringline sensor 136 as schematically illustrated inFIGS. 1 and 3. Thus the stringline sensor 136 comprises the width sensormounted on the machine 12, such that the stringline sensor 136 movesrelative to the objects S1 and S2 when the frame width 32 is varied. Thestringline sensor 136 may be a two-dimensional sensor, or may be used tolocate the position of the right side of the slab 62 solely in thehorizontal plane.

Alternative Reference Object Locations of FIGS. 6A-6F and 7A-7F

In the embodiment seen in FIGS. 1 and 2, the two 3D stringless referenceobjects S1 and S2 are spaced apart longitudinally by a spacing componentparallel to the operating direction 32. Those objects S1 and S2 arelongitudinally fixed relative to the side frame member 14. Thisarrangement is schematically illustrated in FIG. 6A. It is noted that inthe schematic illustrations of FIG. 6A-6F, only the frame members 14, 16and 18 are shown, and the swing legs 42 and ground engaging units 40have been deleted for ease of illustration.

Alternatively, as seen in FIGS. 6B and 6C, the two 3D stringlessreference objects S1 and S2 may be attached to the main frame module 18.In the embodiment of FIG. 6B, the objects S1 and S2 are spaced apartlaterally with a spacing component perpendicular to the operatingdirection 34. In the embodiment of FIG. 6C, the objects S1 and S2 arespaced apart longitudinally.

Another embodiment is illustrated in FIG. 3A, wherein the slipformpaving machine 10 includes a carrier frame 138. The objects S1 and S2are fixedly attached to the carrier frame 138 so that a distance 140between the objects S1 and S2 is fixed by the structure of the carrierframe 138. In the embodiment shown in FIG. 3A the carrier frame 138 isfixed relative to the main frame module 18. The embodiment of FIG. 3A isschematically illustrated in FIG. 6D.

In another alternative embodiment shown in FIG. 3B, the carrier frame138 is fixed at 142 to the left side frame member 14, and a travelingsupport 144 supports the carrier frame 138 from the main frame module 18while allowing relative lateral movement between the carrier frame 138and the main frame module 18. The traveling support 144 may beconstructed as a rolling support using rollers or bearings.Alternatively, the traveling support 144 may be a sliding supportproviding a sliding bearing. The embodiment of FIG. 3B is schematicallyillustrated in FIG. 6E.

FIG. 3C illustrates still another embodiment wherein the carrier frame138 is adjustably positioned on the main frame module 18 on travellingsupports 143 and 145. An adjustment device 147 is connected to the mainframe module 18 at 149 and to the carrier frame 138 at 151. Adjustmentdevice 147 controls the lateral position of carrier frame 138 on themain frame module 18. This allows the carrier frame 138 to be maintainedin a central location spanning a main trajectory 154 of the machine 10as is further described below with regards to FIG. 8A. The embodiment ofFIG. 3C is schematically illustrated in FIG. 6F.

In the various embodiments of FIGS. 6A-6F, the position and orientationof the frame 12 in the external reference system may be determined byinformation from the reference objects S1 and S2, and additionalinformation from the width sensor in any of its embodiments describedabove. Also information from the cross slope sensor 122 may be utilizedto further determine and control the cross slope of the frame 12.

All of the embodiments described above in FIGS. 6A-6F have been withreference to the double telescoping frame 12 shown in FIG. 1.Additionally, similar control systems may be utilized with a modifiedslipform paving machine 10A as shown in FIG. 5 which telescopes only tothe left hand side from its modified main frame module 18A. FIGS. 7A-7Fschematically illustrate various possible positioning arrangements forthe 3D stringless reference objects S1 and S2 on the slipform pavingmachine 10A. In the embodiments of FIG. 5 and FIGS. 7A-7F the secondside frame member 16 is an integral part of the main frame module 18A.

In all of the embodiments the machine frame 12 may be described asincluding first and second side frame members 14 and 16. In theembodiments of FIG. 5 and FIGS. 7A-7F the machine frame may be describedas including the main frame module 18A and having one side member 14laterally movable relative to the main frame module. In the embodimentsof FIGS. 1-3 and FIGS. 6A-6F the machine frame may be described asincluding the main frame module 18 and having both of the side framemembers 14 and 16 laterally movable relative to the main frame module.All of the embodiments may be described as having at least one of theside frame members laterally movable relative to the main frame module.

In FIG. 7A, the reference objects S1 and S2 are fixed to the left sideframe member 14 and are longitudinally spaced apart.

In the embodiment of FIG. 7B, the reference objects S1 and S2 are fixedto the main frame module 18A and are transversely spaced apart.

In the embodiment of FIG. 7C, the reference objects S1 and S2 are fixedon the main frame module 18A and are longitudinally spaced apart.

In FIG. 7D, the reference objects S1 and S2 are mounted on carrier frame138 which is fixed to the main frame module 18A.

In the embodiment of FIG. 7E, the reference objects S1 and S2 are fixedto the carrier frame 138 which is fixed to the left side frame member 14and which is slidingly supported from the main frame module 18A by atraveling support similar to support 144 illustrated in FIG. 3B.

In the embodiment of FIG. 7F, the reference objects S1 and S2 are fixedto the carrier frame 138 which is adjustable in lateral position on themain frame module 18 via travelling supports 143 and 145 and adjustmentdevice 147.

It is also noted that analogous arrangements which are mirror images ofthose shown in FIGS. 6A-6F and 7A-7F may be used.

Variable Spacing Between Reference Objects S1 and S2

In all of the embodiments discussed above the distance between the two3D stringless reference objects S1 and S2 is fixed. Such arrangementsare compatible with commercially available GNSS and total station basedguidance systems which are configured to determine the location andorientation of an object, such as machine 10, within an externalreference system based upon the locations of two points having a fixedspacing. Also from the known geometry of the machine 10, the location ofthose two points determines the location of all other points on themachine 10 within the external reference system.

FIG. 10 is a schematic plan view similar to FIG. 6A, but illustrating adual telescoping machine frame which has the two 3D stringless referenceobjects S1 and S2 mounted on the machine frame such that a distance 156between the objects S1 and S2 is variable. In this embodiment, thecontroller 112 of FIG. 9 will include a controller module 158 as part ofthe computer program 125. The controller module 158 is configured todetect the variable distance 156 between the two reference objects S1and S2 based upon the input signals corresponding to the positions ofthe two 3D stringless reference objects S1 and S2 in the externalreference system. In this embodiment the controller module 158 providesthe width sensor configured to generate a width signal corresponding toa change in frame width or paving width. The controller module 158, inaddition to determining the variable distance 156 between referenceobjects S1 and S2, must be compatible with the overall guidance systemwhich determines the position of all of the points on the machine 10within the external reference system based upon the locations of S1 andS2 and the variable distance 156 between those locations.

In the embodiment of FIG. 10, one reference object S1 is fixed relativeto the laterally movable first side frame member 14 and the otherreference object S2 is fixed relative to the laterally movable secondside frame member 16.

In the embodiment of FIG. 11, one reference object S1 is fixed relativeto laterally movable first side frame member 14 and the other referenceobject S2 is fixed relative to the main frame module 18A.

Also, in some embodiments it may be desirable to fix the position of thetwo reference objects S1 and S2 relative to the two mold parts 52 and54, respectively.

Embodiments like those of FIG. 10 and FIG. 11 can simplify the overallarrangement of reference objects and width sensors because the twovariably spaced reference objects S1 and S2 can provide the dualfunction of both determining the location and height and direction ofthe machine 10 in the external reference system, and sensing thevariable spacing of the objects S1 and S2 corresponding to changes inframe width and paving width. This may eliminate the need for a thirdsensor S3, also referred to as a width sensor.

It is noted that even in a system like that of FIG. 10 or FIG. 11 havinga variable spacing between the reference objects S1 and S2, andincluding the controller module 158, it may be desirable to also use anadditional width sensor S3 of any one of the types described herein. Theadditional width sensor S3 can provide a way to confirm the distancevariations detected between the reference objects S1 and S2.

Methods of Operation

Utilizing the systems described above, a method of operating a slipformpaving machine 10 is provided which permits the slipform paving machine10 to move forward in the operating direction 34 and to mold theconcrete 68 into a concrete slab structure 62 extending between theground engaging units 40 and behind the concrete mold 52, 54. The widthof the concrete slab structure 62 may be varied on the fly as the pavingmachine moves forward.

A human operator of the machine 10 may input to the controller 112 adesired or preset three dimensional path for the machine 10 within theexternal reference system. The path will correspond to a desiredelevation, direction, cross slope and width of the concrete structure tobe molded by the paving machine 10. The path may include a variablewidth for the concrete slab structure.

Based on inputs corresponding to the positions in the external referencesystem of the reference objects S1, S2, S3, and the other signal inputsdescribed herein, the controller 112 can determine any deviation of themachine 10 from the desired path and the controller 112 can control thesteering, height, cross slope and paving width of the machine 10 so thatthe actual path of the machine corresponds to the preset path.

As the concrete slab 62 is being molded, a primarily guidance for theslipform paving machine 10 can be provided by sensing a location in theexternal reference system (either the optical based system 100 orsatellite based system 102) of the 3D stringless reference objects S1and S2, each of which is fixed relative to at least one of the mainframe module 18 and one of the laterally extendable side frame members14 and/or 16. The height and direction of the machine frame 12 withinthe external reference system may be controlled by the controller 112 inresponse to signals corresponding to the positions of the referenceobjects S1 and S2.

In embodiments having a fixed distance between the two reference objectsS1 and S2, as described above with regard to FIGS. 1-7, both of thereference objects S1 and S2 will be fixed relative to the same one ofthe main frame module 18 or one of the laterally extendable side framemembers 14 or 16. In embodiments having a variable distance 156 betweenthe two reference objects S1 and S2 as described above with regard toFIGS. 10 and 11, each of the reference objects S1 and S2 will be fixedrelative to a different one of the main frame module 18 or one of thelaterally extendable side frame members 14 or 16.

As the concrete slab 62 is being formed, the frame width 32 may beadjusted on the fly to thereby adjust the mold width 78 and similarlyadjust a slab width 146 of the concrete slab 62 as schematicallyillustrated in FIGS. 8A, 8B and 8C. Alternatively, in some embodimentsthe mold width may be adjusted independently of the frame width. Theseadjustments may be automatically made by controller 112 in response towidth signals from reference object S3, or from other width sensorsdescribed herein, and in accordance with the predetermined path whichhas been input into the controller 112.

As the concrete slab 62 is being formed, the cross slope may also beadjusted. This adjustment may be automatically made by controller 112 inresponse to cross slope signals from sensor 122 and in accordance withthe predetermined path which has been input into the controller 112.

FIG. 8A schematically illustrates a slab 62 having a first slab width146 and a second slab width 148.

As the slipform paving machine 10 moves forward in the direction 34,when the mold 52, 54 reaches a first location 149, the actuators 24, 26,28 and 30 are actuated to continuously adjust the frame width 32 andthus the mold width 78 as the mold 52, 54 moves through a transitiondistance 150 thus forming a continuous transition 152 in the concreteslab structure 62 from the first slab width 146 to the second slab width148.

In the embodiment schematically illustrated in FIG. 8A, the slab widthis symmetrically extended on both sides of a main trajectory line 154 ofthe paving machine 10.

In the embodiment of FIG. 8B, the slab width is extended asymmetricallyto one side of the main trajectory 154.

In the embodiment of FIG. 8C, the slab width is extended asymmetricallyto both sides of the main trajectory 154.

Similarly, the slab width may be decreased as the paving machine 10moves forward in a manner analogous to any of FIGS. 8A-8C.

Also, as noted above regarding the embodiment of FIG. 3C, it may bedesirable to maintain the carrier frame 138 position so as to equallyspan the main trajectory 154, even if there is an asymmetric telescopingof the frame 12. This is accommodated by the variable positioned carrierframe 138 of FIG. 3C as is schematically illustrated in FIG. 3D.

FIG. 3D schematically illustrates the frame arrangement of FIG. 3C in anasymmetric telescoping mode relative to the main trajectory 154 of theconcrete slab schematically illustrated in FIG. 8A. In FIG. 3D it can beseen that the left side frame member 14 has been extended relative tomain frame module 18 by a distance “a”, whereas the right side framemember 16 has been extended relative to main frame module 18 by a lesserdistance “b”. In order to maintain the carrier frame 138 centrallystraddled on the main trajectory 154, the adjustment device 147 shifts acenter line 139 of the carrier frame 138 to the left relative to acenter line 141 of the main frame module 18 by the distance (a−b)/2.

Thus it is seen that the apparatus and methods of the present inventionreadily achieve the ends and advantages mentioned as well as thoseinherent therein. While certain preferred embodiments of the inventionhave been illustrated and described for purposes of the presentdisclosure, numerous changes in the arrangement and construction ofparts and steps may be made by those skilled in the art, which changesare encompassed within the scope and spirit of the present invention asdefined by the appended claims.

What is claimed is:
 1. A slipform paving machine apparatus, comprising:a machine frame including first and second side frame members, themachine frame being variable in frame width; at least one first sideground engaging unit and at least one second side ground engaging unit,at least one of the ground engaging units being steerable to control adirection of the paving machine apparatus; front and rear first sideheight adjustable supports supporting the first side frame member fromthe at least one first side ground engaging unit; at least one secondside height adjustable support supporting the second side frame memberfrom the at least one second side ground engaging unit; a mold supportedfrom the machine frame beneath the machine frame and laterally betweenthe at least one first side ground engaging unit and the at least onesecond side ground engaging unit, the mold being configured to moldconcrete into a concrete structure having an upper surface and lateralconcrete sides as the machine moves forward in an operating direction,the mold being variable in mold width so as to vary a paving width ofthe concrete structure; at least two three-dimensional (3D) stringlessreference objects configured to correspond to positions of at least twopoints on the machine frame relative to an external reference system; awidth actuator configured to vary the paving width; a width sensorconfigured to generate a width signal corresponding to a change in thepaving width; and a controller configured to receive input signalscorresponding to the positions of the 3D stringless reference objects inthe external reference system, and to receive the width signal from thewidth sensor, the controller also configured to control heightadjustment of one or more of the height adjustable supports, to controlsteering of the at least one steerable ground engaging unit, and tocontrol the width actuator so that the paving width can be varied as themachine moves forward in the operating direction.
 2. The apparatus ofclaim 1, wherein: the machine frame includes a main frame module, and atleast one of the side frame members is laterally movable relative to themain frame module to vary the frame width.
 3. The apparatus of claim 2,wherein: both of the side frame members are laterally movable relativeto the main frame module to vary the frame width.
 4. The apparatus ofclaim 1, wherein: a distance between the at least two 3D stringlessreference objects is fixed.
 5. The apparatus of claim 4, wherein: thewidth sensor comprises an additional 3D stringless reference objectconfigured such that the additional 3D stringless reference object movesrelative to the at least two 3D stringless reference objects when thepaving width is varied.
 6. The apparatus of claim 4, wherein: the widthsensor comprises an extension sensor configured to detect an extensionof the paving width.
 7. The apparatus of claim 4, wherein: the widthsensor comprises a stringline sensor mounted on the machine frame suchthat the stringline sensor moves relative to the at least two 3Dstringless reference objects when the frame width is varied, so that astringline fixed in the external reference system can be used to controlchanges in frame width.
 8. The apparatus of claim 4, wherein: the atleast two 3D stringless reference objects are spaced apartlongitudinally with a spacing component parallel to the operatingdirection.
 9. The apparatus of claim 8, wherein: the at least two 3Dstringless reference objects are longitudinally fixed relative to one ofthe side frame members.
 10. The apparatus of claim 8, wherein: themachine frame includes a main frame module, and at least one of the sideframe members is laterally movable relative to the main frame module tovary the frame width; and the at least two 3D stringless referenceobjects are longitudinally fixed relative to the main frame module. 11.The apparatus of claim 4, wherein: the at least two 3D stringlessreference objects are spaced apart laterally with a spacing componentperpendicular to the operating direction.
 12. The apparatus of claim 11,wherein: the machine frame includes a main frame module, and at leastone of the side frame members is laterally movable relative to the mainframe module to vary the frame width; and the at least two 3D stringlessreference objects are laterally fixed relative to the main frame module.13. The apparatus of claim 11, wherein: the machine frame includes amain frame module, and at least one of the side frame members islaterally movable relative to the main frame module to vary the framewidth; and the at least two 3D stringless reference objects arelaterally fixed relative to the at least one laterally movable sideframe member.
 14. The apparatus of claim 11, wherein: the machine frameincludes a main frame module, and at least one of the side frame membersis laterally movable relative to the main frame module to vary the framewidth; and the machine further includes a carrier frame having the atleast two 3D stringless reference objects fixedly attached to thecarrier frame so that the distance between the at least two 3Dstringless reference objects is fixed, the carrier frame being fixedrelative to one of the main frame module and the at least one laterallymovable side frame member.
 15. The apparatus of claim 14, wherein: thecarrier frame is fixed relative to the at least one laterally movableside frame member; and the machine further includes a travelling supportbetween the carrier frame and the main frame module for supporting thecarrier frame from the main frame module while allowing relative lateralmovement between the carrier frame and the main frame module.
 16. Theapparatus of claim 11, wherein: the machine frame includes a main framemodule, and at least one of the side frame members is laterally movablerelative to the main frame module to vary the frame width; and themachine further includes a carrier frame having the at least two 3Dstringless reference objects fixedly attached to the carrier frame sothat the distance between the at least two 3D stringless referenceobjects is fixed, the carrier frame being supported from the main framemodule and being laterally adjustably positioned relative to the mainframe module.
 17. The apparatus of claim 1, wherein: the at least two 3Dstringless reference objects include global navigation satellite system(GNSS) sensors.
 18. The apparatus of claim 1, wherein: the at least two3D stringless reference objects include reflectors for a ground basedoptical surveying system.
 19. The apparatus of claim 1, wherein: one ofthe at least two 3D stringless reference objects includes a globalnavigation satellite system (GNSS) sensor and the other of the at leasttwo 3D stringless reference objects includes a reflector for a groundbased optical surveying system.
 20. The apparatus of claim 1, furthercomprising: a cross slope sensor mounted on the machine frame; andwherein the controller is configured to generate a cross slopeadjustment signal to control a cross slope of the machine frame byadjustment of one or more of the height adjustable supports.
 21. Theapparatus of claim 1, wherein: the width actuator includes a piston andcylinder configured to extend and contract the frame width.
 22. Theapparatus of claim 1, wherein: the width actuator includes a steeringsystem configured to steer the ground engaging units relative to eachother so as to vary the frame width.
 23. The apparatus of claim 1,wherein: the at least two 3D stringless reference objects are mountedrelative to the machine frame such that a distance between the at leasttwo 3D stringless reference objects is variable; and the width sensorcomprises a controller module configured to detect the distance betweenthe at least two 3D stringless reference objects based upon the inputsignals corresponding to the positions of the at least two 3D stringlessreference objects in the external reference system.
 24. The apparatus ofclaim 23, wherein: the machine frame includes a main frame module, andat least one of the side frame members is laterally movable relative tothe main frame module to vary the frame width; and one of the at leasttwo 3D stringless reference objects is fixed relative to the at leastone laterally movable side frame member, and the other of the at leasttwo 3D stringless reference objects is fixed relative to the main framemodule.
 25. The apparatus of claim 23, wherein: the machine frameincludes a main frame module, and both of the side frame members arelaterally movable relative to the main frame module to vary the framewidth; and one of the at least two 3D stringless reference objects isfixed relative to each of the side frame members.
 26. The apparatus ofclaim 1, wherein: the mold is attached to the frame such that the moldvaries in mold width as the frame width is varied, and thus the pavingwidth varies as the frame width is varied.
 27. A method of operating aslipform paving machine, the method comprising: (a) providing a slipformpaving machine including: a machine frame including a main frame moduleand at least one laterally extendable side frame member, the at leastone laterally extendable side frame member being laterally extendablerelative to the main frame module to vary a frame width; at least onefirst side ground engaging unit and at least one second side groundengaging unit; front and rear first side height adjustable supportssupporting the machine frame from the at least one first side groundengaging unit; at least one second side height adjustable supportsupporting the machine frame from the at least one second side groundengaging unit; and a concrete mold supported from the machine framebeneath the machine frame and laterally between the at least one firstside ground engaging unit and the at least one second side groundengaging unit, the mold having a variable mold width; (b) moving theslipform paving machine forward in an operating direction and moldingconcrete into a concrete slab structure extending between the groundengaging units and behind the concrete mold, the structure having anupper surface and lateral concrete sides; (c) during step (b) sensing alocation in an external reference system of at least two 3D stringlessreference objects, each of the objects being fixed relative to at leastone of the main frame module and the at least one laterally extendableside frame member; (d) controlling a direction and height of the machineframe with an automatic control system in response to signalscorresponding to the locations of the two 3D stringless referenceobjects; and (e) at some time during step (b) continuously adjusting themold width and forming a continuous transition in the concrete slabstructure from a first slab width to a second slab width.
 28. The methodof claim 27, further comprising: during step (e) receiving from a widthsensor a width signal corresponding to a change in the mold width; andcontrolling a width actuator with the automatic control system inresponse to the width signal and thereby facilitating the adjustment ofmold width.
 29. The method of claim 28, wherein: during step (e) adistance between the at least two 3D stringless reference objects staysfixed.
 30. The method of claim 29, wherein: the width sensor comprisesan additional 3D stringless reference object mounted on machine framesuch that, during step (e) the additional 3D stringless reference objectmoves relative to the at least two 3D stringless reference objects whenthe mold width is adjusted.
 31. The method of claim 29, wherein: thewidth sensor comprises an extension sensor configured to detect anextension of the width actuator.
 32. The method of claim 29, wherein:the width sensor comprises a stringline sensor mounted on machine framesuch that during step (e) the stringline sensor moves relative to the atleast two 3D stringless reference objects when the frame width isvaried, so that a stringline fixed in the external reference systemdetermines changes in mold width.
 33. The method of claim 29, wherein:in step (c), the at least two 3D stringless reference objects are spacedapart longitudinally with a spacing component parallel to the operatingdirection.
 34. The method of claim 29, wherein: in step (c), the atleast two 3D stringless reference objects are spaced apart laterallywith a spacing component perpendicular to the operating direction. 35.The method of claim 34, wherein: in step (c), the at least two 3Dstringless reference objects are laterally fixed relative to the mainframe module.
 36. The method of claim 34, wherein: in step (c), the atleast two 3D stringless reference objects are laterally fixed relativeto the at least one laterally movable side frame member.
 37. The methodof claim 34 wherein: in step (c), the machine further includes a carrierframe having the at least two 3D stringless reference objects fixedlyattached to the carrier frame so that the distance between the at leasttwo 3D stringless reference objects is fixed, the carrier frame beingfixed relative to one of the main frame module and the at least onelaterally movable side frame member.
 38. The method of claim 37,wherein: the carrier frame is fixed to the at least one laterallymovable side frame member; and the machine further includes a travellingsupport between the carrier frame and the main frame module forsupporting the carrier frame from the main frame module while allowingrelative lateral movement between the carrier frame and the main framemodule.
 39. The method of claim 34 wherein: in step (c), the machinefurther includes a carrier frame having the at least two 3D stringlessreference objects fixedly attached to the carrier frame so that thedistance between the at least two 3D stringless reference objects isfixed, the carrier frame being adjustably positioned on the main framemodule.
 40. The method of claim 27, wherein: the at least two 3Dstringless reference objects include global navigation satellite system(GNSS) sensors.
 41. The method of claim 27, wherein: the at least two 3Dstringless reference objects include reflectors for a ground basedoptical surveying system.
 42. The method of claim 27, wherein: one ofthe at least two 3D stringless reference objects includes a globalnavigation satellite system (GNSS) sensor and the other of the at leasttwo 3D stringless reference objects includes a reflector for a groundbased optical surveying system.
 43. The method of claim 27, wherein: themachine further includes a cross slope sensor mounted on the machineframe; and the method further includes generating a cross slopeadjustment signal with the cross slope sensor and controlling a crossslope of the machine frame by adjustment of one or more of the heightadjustable supports.
 44. The method of claim 27, wherein: the widthactuator includes a piston and cylinder and step (e) includes extendingor contracting the width actuator to facilitate extending or contractingthe mold width.
 45. The method of claim 27, wherein: the width actuatorincludes a steering system and step (e) includes steering the groundengaging units relative to each other so as to vary the frame width. 46.The method of claim 27, wherein: during step (e) a distance between theat least two 3D stringless reference objects stays is varied.
 47. Aslipform paving machine apparatus, comprising: a machine frame includinga main frame module and at least one laterally extendable side framemember, the at least one laterally extendable side frame member beinglaterally extendable relative to the main frame module to vary a framewidth; at least one first side ground engaging unit and at least onesecond side ground engaging unit; front and rear first side heightadjustable supports supporting the machine frame from the at least onefirst side ground engaging unit; at least one second side heightadjustable support supporting the machine frame from the at least onesecond side ground engaging unit; a variable width mold supported fromthe machine frame beneath the machine frame and laterally between the atleast one first side ground engaging unit and the at least one secondside ground engaging unit, the mold being configured to mold concreteinto a concrete structure having an upper surface and lateral concretesides as the machine moves forward in an operating direction; at leasttwo three-dimensional (3D) stringless reference objects configured tocorrespond to positions of the objects relative to an external referencesystem; and a carrier frame having the at least two 3D stringlessreference objects fixedly attached to the carrier frame so that adistance between the at least two 3D stringless reference objects isfixed, the carrier frame being supported from at least one of the mainframe module and the at least one laterally movable side frame member.48. The apparatus of claim 47, wherein: the carrier frame is fixedrelative to one of the main frame module and the at least one laterallymovable side frame member, and the carrier frame is movable relative tothe other of the main frame module and the at least one laterallymovable side frame member.
 49. The apparatus of claim 48, wherein: thecarrier frame is fixed to the at least one laterally movable side framemember; and the machine further includes a travelling support betweenthe carrier frame and the main frame module for supporting the carrierframe from the main frame module while allowing relative lateralmovement between the carrier frame and the main frame module.
 50. Theapparatus of claim 47, wherein: the carrier frame is laterallyadjustable positioned on the main frame module.
 51. The apparatus ofclaim 47, further comprising: a width actuator configured to vary theframe width; a width sensor arranged to generate a width signalcorresponding to a change in the frame width; and a controllerconfigured to receive input signals from the 3D stringless referenceobjects and the width sensor, the controller also configured to controlheight adjustment of one or more of the side height adjustable supportsand to control the width actuator so that the frame width can be variedas the machine moves forward in the operating direction.